I have a trailer electrical disconnect switch located in the C/S bay just behind the back wheels. Perhaps you have such a switch and it's set to OFF?
Another ideas is fuses. Is there perhaps a fuse that controls the toad electrical connector? I would read all the fuse labels usually on the inside of the relavent bay doors to see if any fuses in that bay are related to your issue. There are three bay doors on mine which have VDC fuses (under drivers seat, both sides behind tag axel).